Cellular cordless telephone which polls information in a memory to determine a pre-selected preference and a stored availability of call forwarding

ABSTRACT

A cellular cordless telephone (10) operates with both a cordless base station (180) and a cellular base station (190) and cellular control terminal (196). In one embodiment (FIG. 2 ), a cellular cordless telephone (100) includes a cellular transceiver (120), antenna (128), keyboard (140), a display (180), handset (160), and microcomputer (130) together with a cordless transceiver (110) and antenna (118), all of which may be in a single housing. In another embodiment (FIG. 3 ), a cellular cordless telephone (200) includes a cellular telephone (220) and a cordless telephone transceiver (210) which may be a plugable module. Whenever cellular cordless telephone (10) is within range of cordless base station (180), telephone calls may be made over the cordless radio channel or transferred from the cellular radio channels to the cordless radio channel. If the cellular cordless telephone (10) thereafter moves out of range of the cordless base station (180), telephone calls may be made over the cellular radio channels or transferred from the cordless radio channel to one of the cellular telephone channels.

This is continuation of application Ser. No. 08/134,431, filed Oct. 12,1993 and now abandoned, which is a division of application Ser. No.08/103,169 filed Aug. 6, 1993, now abandoned, which is a continuation ofapplication Ser. No. 07/826,322, filed Jan. 2, 1992 and now abandoned,which is a division of application Ser. No. 07/660,180 filed Feb. 25,1991 and now U.S. Pat. No. 5,127,042, which is a continuation of Ser.No. 07/516,375 filed Apr. 30, 1990 and now abandoned, which in turn is adivision of application Ser. No. 07/249,041 filed on Sep. 23, 1988 andnow U.S. Pat. No. 4,989,230.

BACKGROUND OF THE INVENTION

The present invention is generally related to cellular telephones andmore particularly to an improved cellular cordless telephone forproviding both cellular and cordless telephone services.

In the prior art, cordless telephones typically are used in the home toallow the user to place and receive telephone calls at any pointthroughout the house. Such cordless telephones are connected to theuser's telephone landline. However, due to their limited range, suchcordless telephones are not suitable for use in vehicles. Vehicularcommunications are typically achieved by means of radio telephonesystems, the most prevalent being cellular telephone systems. A cellulartelephone allows the user to place and receive telephone calls at anypoint throughout a large metropolitan area. However, the cost of acellular telephone call is as much as seven times the cost of a cordlesstelephone call, since cordless telephone calls are made by way of theuser's telephone landline and cost the same as landline telephone calls,while cellular telephone calls are made by way of expensive cellularbase stations and cellular switching equipment and cost much more thanlandline telephone calls.

OBJECTS OF THE INVENTION

Accordingly, it is an object of the present invention to provide animproved cellular cordless telephone that may place both cellulartelephone calls and cordless telephone calls.

It is another object of the present invention to provide an improvedcellular cordless telephone that automatically operates as a cordlesstelephone whenever it is in range of its corresponding cordless basestation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a cellular cordless telephone systemembodying the present invention.

FIG. 2 is a block diagram of a cellular cordless telephone embodying thepresent invention.

FIG. 3 is a block diagram of another embodiment of a cellular cordlesstelephone according to the present invention.

FIG. 4 is a flow chart for the process used by the cellular cordlesstelephones in FIGS. 2 and 3 for placing and receiving cellular andcordless telephone calls.

FIG. 5 is a flow chart for the process used by the cellular cordlesstelephones in FIGS. 2 and 3 for originating a telephone call as acellular telephone call or a cordless telephone call according to userselectable preference.

FIG. 6 is a flow chart for the process used by the cellular cordlesstelephones in FIGS. 2 and 3 for receiving a telephone call as a cellulartelephone call or a cordless telephone call according to user selectablepreference.

FIG. 7 is a flow chart for the process used by the cellular cordlesstelephones in FIGS. 2 and 3 for simultaneously processing both acellular telephone call and a cordless telephone call and three-waylinking both calls.

FIG. 8 is a flow chart for the process used by the cellular cordlesstelephones in FIGS. 2 and 3 for automatically transfering between acellular telephone call and a cordless telephone call.

FIG. 9 is a block diagram of audio switch 150 in the cellular cordlesstelephone in FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIG. 1, there is illustrated a block diagram of a cellular cordlesstelephone system embodying the present invention. The system includes atelephone company phone system (TELCO) 184, connected by telephonelandlines to a cordless base station 180 having a landline telephonenumber located in a home or office 181 and to a community cordless basestation 188 having a landline telephone number in another office,building, or other geographical location. Cordless base stations 180 and188 communicate with the cellular cordless telephone (CCT) 10 throughantennas 182 and 189. Antennas 182 and 189 may be implemented astelescoping whip antennas. Cordless base stations 180 and 188 may be anyconventional cordless base station, such as, for example, the basestation shown and described in Panasonic operating instructions,entitled "Cordless phone Model No. KX-T3000 EASA-PHONE", published byand available from the Panasonic Company, One Panasonic Way, Secaucus,N.J. 07094. Additional community cordless base stations 188 may belocated throughout a metropolitan area for providing shared telephoneservice to CCTs 10. In this case, cordless base station 188 may includeadditional equipment for billing calls to the cellular telephone numberof CCT 10.

Also connected through telephone landlines to the same or a differenttelephone company phone system (TELCO) 198 is the cellular controlterminal 196 (see U.S. Pat. No. 4,268,722) with its associated cellularbase station(s) 190 (see U.S. Pat. No. 4,485,486 incorporated herein byreference). Cellular base station 190 incorporates both a receiveantenna 192 and a transmit antenna 194 (see U.S. Pat. No. 4,369,520incorporated herein by reference) for communicating with CCTs 10.

CCT 10 may be a mobile unit installed in a vehicle, a transportable unitwhich is a mobile unit and battery installed in a carrying case, or ahand-held portable unit. CCT 10 includes an antenna 118 for the cordlessradio channels and an antenna 128 for the cellular radio channels asillustrated by the embodiment of CCT 200 in FIG. 3, or may include asingle antenna, is illustrated by the embodiment of CCT 100 in FIG. 2.In the U.S.A., the cordless radio channels are in the frequency bandfrom 46-49 mHz and the cellular radio channels are in the frequency bandfrom 824-894 mHz.

In FIG. 2, there is illustrated a detailed block diagram of a firstembodiment of a CCT 100 according to the present invention. CCT 100includes a cordless telephone transceiver 110, antenna 118, cellulartelephone transceiver 120, antenna 128, microcomputer 130, keypad 140,display 180, audio switch 150, and handset 160 including speaker 162 andmicrophone 164. Alternatively, as shown by dashed-lines in FIG. 2,cordless telephone transceiver 110 and cellular telephone transceiver120 may be coupled to a single antenna 119 in place of antennas 118 and128 by way of low-pass filter 185 and high-pass filter 187,respectively. Cordless telephone transceiver 110 may be any conventionalcordless telephone transceiver, such as, for example the transceivershown and described in the aforementioned Panasonic operatinginstructions, entitled "Cordlessphone Model No. KX-T3000 EASA-PHONE".Cellular telephone transceiver 120, microcomputer 130, keypad 140, andhandset 160 likewise may be any commercially available cellulartransceiver, such as, for example, the transceiver shown and describedin Motorola instruction manual number 68P81049E55, entitled "DYNATACCellular Mobile Telephone", published by and available from Motorola C &E Parts, 1313 East Algonquin Road, Schaumburg, Ill. 60196.

Referring to FIG. 9, audio switch 150 may be implemented with two-to-onemultiplexing analog switches. 151-155 which select between audio signalsof audio circuitry 116 in cordless transceiver 110 and audio circuitry126 in cellular transceiver 120 under control of select signals SELECT1,SELECT2 and LINK from microcomputer 130. Select signal SELECT2 enablesswitches 151 and 152 when it has a binary one state, select signalSELECT1 enables switches 153 and 154 when it has a binary one state, andselect signal LINK enables switches 152, 154 and 155 when it has abinary one state. Depending on which is enabled, analog switches 151 and153 couple speaker 162 to receive audio from audio circuitry 116 andaudio circuitry 126, respectively. Similarly, depending on which isenabled, analog switches 152 and 154 couple microphone 164 to transmitaudio of audio circuitry 116 and audio circuitry 126, respectively. Ifthree-way linking is selected, analog switches 152 and 154 couplemicrophone 164 to transmit audio of both audio circuitry 116 and audiocircuitry 126, and analog switch 155 couples speaker 162 to receiveaudio of both audio circuitry 116 and audio circuitry 126 by way ofsumming amplifier 159.

Referring to CCT 100 in FIG. 2, microcomputer 130 is programmed inaccordance with FIGS. 4-8 for operating as a cellular telephone, acordless telephone, or a cellular cordless telephone. That is, accordingto the present invention, CCT 100 may simultaneously operate as acellular telephone and a cordless telephone. When operating as acellular telephone, control signals 131 TX ENABLE and 132 RX ENABLE ofmicrocomputer 130 enable cellular transmitter 124 and cellular receiver122, respectively. In addition to control signals 131 and 132 tocellular transceiver 120, microcomputer 130 also monitors controlsignals 133 RSSI, 134 RX DATA and 135 TX DATA for detecting signalstrength, for detecting receive data and for sending transmit data,respectively, used in operation of cellular transceiver 120. Whenoperating as cordless telephone, control signals 141 and 146 ofmicrocomputer 130 enable cordless receiver 112 and cordless transmitter114, respectively. In addition to control signals 141 and 146 tocordless transceiver 110, microcomputer 130 also monitors controlsignals 142 SIGNAL QUALITY, 143 RING, 144 RX SECURITY CODE and 145 TXSECURITY CODE for detecting signal strength, ringing, and the receivesecurity code, and for sending the transmit security code and dialeddigits, respectively, used in operation of cordless transceiver 110.Dialed digits may also be encoded by keypad 140 as conventionalmulti-frequency tones which are coupled to transmit audio of cordlesstransceiver 110 by audio switch 150 during cordless operation.

Referring next to FIG. 3, there is illustrated a block diagram ofanother embodiment of a cellular cordless telephone (CCT) 200 accordingto the present invention. CCT 200 includes a cordless telephonetransceiver 210 in a separate housing with antenna 218 and connector270, and a cellular telephone 220 in a separate housing with antenna 228and connector 272. Cordless telephone transceiver 210 may be a plug-inaccessory which couples via connectors 270 and 272 to cellular telephone220. When cordless telephone transceiver 210 is plugged intomicrocomputer 230 of cellular telephone 220, it operates in accordancewith FIGS. 4-8. Cellular telephone 220 includes cellular transmitter222, cellular receiver 224, microcomputer 230, keypad 240, display 280,audio circuitry 226, audio switch 250 and handset 260 including speaker262 and microphone 264. Cordless telephone transceiver 210 may be anyconventional cordless telephone transceiver, such as, for example thetransceiver shown and described in the aforementioned Panasonicoperating instructions, entitled "Cordlessphone Model No. KX-T3000EASA-PHONE". Cellular telephone 220 likewise may be any commerciallyavailable cellular transceiver, such as, for example, the transceivershown and described in the aforementioned Motorola instruction manualnumber 68P81049E55, entitled "DYNATAC Cellular Mobile Telephone".

Microcomputer 230 of cellular telephone 220 is coupled to the cordlesstelephone transceiver 210 via the same control signals used in FIG. 2.These control signals are TX/RX enable signals, signal quality signal,ring signal and TX/RX security code signals.

Audio circuitry 226 of cellular telephone 220 is coupled to audio switch250 which can be implemented with two-to-one multiplexing analogswitches (see FIG. 9) which select between audio signals from audiocircuitry 226 and cordless telephone transceiver 210.

Referring now to FIG. 4, there is illustrated a flow chart for theprocess used by the CCTs 100 and 200 in FIGS. 2 and 3, respectively, forplacing and receiving cellular and cordless telephone calls. Entering atblock 302, the user activates the CCT. The microcomputer 130 and 230monitors both the cellular and cordless systems for availability thereofand for incoming and outgoing calls. If the cellular system and/orcordless system are available, a corresponding availability indicator isenabled in display 180 and 280. In cellular systems, the microcomputerscans pre-selected signalling channels to determine if cellular serviceis available. Next, at decision block 304, a check is made to determineif a call has been received. If not, NO branch is taken to decisionblock 316 to determine if a call has been initiated by the user of theCCT. If not, NO branch is taken back to block 304 to continue monitoringboth the cellular and cordless systems for telephone calls.

Returning to decision block 304, if an incoming call has been received,YES branch is taken to decision block 306 where a check is made todetermine if the incoming call is a cellular call. If so, YES branch istaken to block 308 where a cellular call indicator is activated orentered in display 180 and 280, and the incoming call is connected as acellular call (e.g., in FIG. 2, cellular transceiver 120 is enabled bymicrocomputer 130). If the incoming call is not a cellular call, NObranch is taken from block 306 to block 320 where a cordless callindicator is activated or entered in display 180 and 280, and theincoming call is connected as a cordless call (e.g., in FIG. 2, cordlesstransceiver 110 is enabled by microcomputer 130).

Returning to decision block 316, if a call has been initiated by theuser of the CCT, YES branch is taken to decision block 318 where a checkis made to determine if the initiated call is a cellular call. If so,YES branch is taken to block 308 where the initiated call is connectedas a cellular call. If the initiated call is not a cellular call, NObranch is taken from decision block 318 to block 320 where the initiatedcall is connected as a cordless call.

Referring now to FIG. 5, there is illustrated a flow chart for theprocess used by the CCTs 100 and 200 in FIGS. 2 and 3, respectively, fororiginating a telephone call as a cellular telephone call or a cordlesstelephone call according to user selectable preference.

Entering at block 400, the user activates the CCT. Next, at block 402, acheck is made to determine if a call has been originated by the CCT. Ifnot, NO branch is taken to wait for a call to be originated. If a callhas been originated, YES branch is taken from decision block 402 todecision block 404, where a check is made to determine if the user'spreference is for cordless phone operation. If not, NO branch is takento block 406 to determine if a call can be placed on the cellularsystem. If so, YES branch is taken to block 416 where the callorigination is connected as a cellular call. If not, NO branch is takento decision block 408 to determine if a call can be successfully placedon the cordless system. Referring back to decision block 404, ifpreference is for cordless, YES branch is also taken to decision block408. If a cordless call can be successfully placed, YES branch is takenfrom decision block 408 to decision block 414 where the call isconnected as a cordless call. If not, NO branch is taken to decisionblock 410 to determine if a call had been tried unsuccessfully on thecellular system. If so, YES branch is taken to block 402 to wait for acall origination. If not, NO branch is taken to decision block 406 todetermine if the call can be placed on the cellular system.

Referring now to FIG. 6, there is illustrated a flow chart for theprocess used by the CCTs 100 and 200 in FIGS. 2 and 3, respectively, forreceiving a telephone call as a cellular telephone call or a cordlesstelephone call according to user selectable preference.

Entering at block 500, the user activates the CCT. Next, at decisionblock 502, a check is made to determine if a call is being received bythe CCT. If not, NO branch is taken back to decision block 502. If acall has been received, YES branch is taken from decision block 502 todecision block 504 to determine if the user's system preference matchesthe system of the incoming call. If so, YES branch is taken to decisionblock 508 to determine if the call is on the cordless system. If so, theYES branch is taken to block 510 where the incoming call is connected asa cordless call. If not, the NO branch is taken to block 512 where theincoming call is connected as a cellular call.

Returning to decision block 504, if the user's system preference doesnot match the system of the incoming call, NO branch is taken todecision block 506 to determine if the preference is for the cordlesssystem. If so, the YES branch is taken to decision block 514 todetermine if the CCT is within range of the cordless base station (e.g.,by sending the transmit security code and waiting for the receivesecurity code from the cordless base station). If not, the NO branch istaken to block 512 where the incoming call is connected as a cellularcall. If the cellular cordless telephone is within range of the cordlessbase station, YES branch is taken from decision block 514 to decisionblock 516 to determine if the cellular system will forward theunanswered incoming call to the landline of the cordless base stationwhen the cellular phone cannot be reached. This type of service isgenerally referred to as "call forwarding" (call forwarding is aconvention process which is described in a person's telephone directory)and can be determined by polling stored information in the memoryassociated with the CCT microcomputer. If not, NO branch is taken toblock 512 where the incoming call is connected as a cellular call. Ifthe cellular system will forward the unanswered incoming call, YESbranch is taken from decision block 516 to block 518 where the cellularpage from the cellular base station is ignored and thereafter todecision block 502 to wait for the incoming call to be received as acordless call.

Returning to decision block 506, if the preference is for a cellularcall, NO branch is taken to decision block 520 to determine if the CCTis within range of the cellular base stations (does it have cellularservice). This is typically determined by scanning and selecting thestrongest signalling channel from the surrounding cellular basestations. If not, NO branch is taken to block 510, where the incomingcall is connected as a cordless call. If the CCT is within range of thecellular base stations, YES branch is taken from decision block 520 todecision block 522 to determine if the landline system will forward theunanswered incoming call to the cellular system. This type of service isgenerally referred to as "call forwarding" (call forwarding is aconventional process which is described in a person's telephonedirectory) and can be determined by polling stored information in thememory associated with the CCT microcomputer. If not, NO branch is takento block 510 where the incoming call is connected as a cordless call. Ifthe landline telephone system will forward the unanswered incoming call,YES branch is taken from decision block 522 to block 524 where thecordless page from the cordless base station is ignored and thereafterback to decision block 502 to wait for the incoming call to be receivedas a cellular call.

Referring now to FIG. 7, there is illustrated a flow chart for theprocess used by the CCTs 100 and 200 in FIGS. 2 and 3, respectively, forsimultaneously processing both a cellular telephone call and a cordlesstelephone call and, if desired, three-way linking both calls.

Entering at block 600, the user activates the CCT. Next, at block 602,one call is assumed to be in process on either the cellular system orcordless system. Proceeding from block 602 to decision block 604, acheck is made to determine if a call has been received on the oppositesystem from the call in process. If so, YES branch is taken to decisionblock 608 to determine if the user has selected the dual-mode feature(e.g., by entering a predetermined code from the keypad). If not, NObranch is taken back to decision block 604 and the current call remainsin process. If the user has selected the dual-mode feature, YES branchis taken from decision block 608 to block 610 which alerts the user ofan incoming call on the alternate system. This type of service isgenerally referred to as "call waiting". Next, at decision block 612, acheck is made to see if the user acknowledges the second call. If not,NO branch is taken back to decision block 604 and the current callremains in process. If the user acknowledges the second call (e.g., byflashing the hookswitch), YES branch is taken from decision block 612 todecision block 614 to determine if the user has selected three-waylinking (e.g., by entering a predetermined code from the keypad). If so,YES branch is taken to block 616 which enables three-way linking of theuser and the two calls, each of which is on a different system.Three-way linking may be accomplished by switchably coupling thecombined receive audio signals from summing amplifier 159 via analoggate 155 to the speaker, and enabling both transmit audio switches 152and 154 in FIG. 9. If the user has not selected three-way linking, NObranch is taken from decision block 614 to block 618 to process bothcalls simultaneously, one over each system, but selection between themis made by the user so that only one party is in conversation with theuser at a time. Selection between the calls may be made pressing apre-selected key or set of keys on the keypad.

Returning to decision block 604, if a call has not been received on theopposite system, NO branch is taken to decision block 606 to determineif a call has been originated on the opposite system. If not, NO branchis taken back to decision block 604. If a call has been originated onthe opposite system, YES branch is taken from decision block 606 todecision block 614 to determine if the user wants three-way linking, asdescribed hereinabove.

Referring now to FIG. 8, there is illustrated a flow chart for theprocess used by the CCTs 100 and 200 in FIGS. 2 and 3, respectively, forautomatically transfering between a cellular telephone call and acordless telephone call.

Entering at block 700, the user activates the CCT. Next at block 702, acall is assumed to be in process on one of the two systems. Proceedingfrom block 702 to decision block 704, a check is made to determine ifthe call in process is on the cordless system. If so, YES branch istaken to decision block 708 to determine if the CCT is still withinrange of the cordless base stations (e.g., signal quality is good). Ifso, YES branch is taken back to decision block 704. If the cellularcordless telephone is out of range of the cordless base stations, NObranch is taken from decision block 708 to decision block 710 todetermine if the user has selected transfer of the cordless call to thecellular system (e.g., by entering a predetermined code from thekeypad). If so, YES branch is taken to block 714 where an attempt ismade to transfer the cordless call to the cellular system. Assuming thecalled party has "call waiting", the transfer is attempted byoriginating another call on the cellular system and waiting for thecalled party to answer. Thereafter, the path returns to decision block704. If the user has not selected call transfer, NO branch is taken fromdecision block 710 to block 712 where the cordless call is maintained aslong as possible. Returning to decision block 704, if the call is not onthe cordless system, NO branch is taken to decision block 706 todetermine if the CCT is still within range of the cellular base stations(e.g., signal quality is good). If so, YES branch is taken back todecision block 704. If the CCT is out of range of the cellular basestations, NO branch is taken from decision block 706 to decision block716 to determine if the user has selected transfer of the cellular callto the cordless system (e.g., by entering a predetermined code from thekeypad). If not, NO branch is taken to block 720 where the cellular callis maintained as long as possible. If the user has selected calltransfer, YES branch is taken from decision block 716 to block 718 wherean attempt is made to transfer the cellular call to the cordless system.Assuming the called party has "call waiting" the transfer is attemptedby originating another call on the cordless system and waiting for thecalled party to answer. Thereafter, the path returns to decision block704.

In summary, a unique cellular cordless telephone has been described thatmay be advantageously utilized for making both cellular telephone callsand cordless telephone calls. Whenever the cellular cordless telephoneis within range of the cordless base station, telephone calls arepreferably originated on the cordless system, or if currently inprocess, are transferred to the cordless telephone system.

We claim:
 1. A method of receiving incoming telephone calls in acellular cordless telephone that has a memory and can receive a callaccording to a preselected preference of either cellular telephone callsto a cellular telephone number on cellular radio channels of a cellulartelephone system or cordless telephone calls on at least one cordlessradio channel of a base station coupled to a telephone landline having alandline telephone number in a landline telephone system, said landlinetelephone number having call forwarding and being call forwarded by thelandline telephone system to said cellular telephone number when notanswered after a predetermined number of rings, said cellular telephonenumber having call forwarding and being call forwarded by the cellulartelephone system to said landline telephone number when not answeredafter a predetermined number of rings, the preselected preference andthe availability of call forwarding being stored as predeterminedinformation in the memory of the cellular cordless telephone, saidmethod comprising the steps of:polling the predetermined information inthe memory to determine the stored pre-selected preference and thestored availability of call forwarding; accepting an incoming telephonecall when said incoming telephone call matches said stored preselectedpreference; ignoring an incoming telephone call when said incomingtelephone call does not match said stored preselected preference andwhen the stored availability of call forwarding has been determined; andaccepting a subsequent incoming call when said subsequent incoming callmatches said stored preselected preference.